This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Stress urinary incontinence (SUI) is a common condition with significant morbidity in older women. SUI occurs when the intravesicle pressure exceeds the intraurethral pressure without detrusor muscle contraction. It is believed to result from laxity or weakness of the pelvic floor muscles and connective tissues that support the bladder neck. The main muscular support structure of the pelvic floor is the levator ani muscle. Animal studies have shown that lowering of testosterone concentrations is associated with loss of levator muscle mass;conversely, testosterone administration in female rats increases the mass of levator ani muscle. There are no published studies of testosterone effects on human levator ani muscle mass and pelvic floor muscle strength. Based on the existing knowledge that post-menopausal women have lower levels of androgens and the current opinion of the mechanism of SUI, this pilot study will determine whether testosterone administration to post-menopausal women with low testosterone levels and SUI will lead to gains in levator ani mass and strength, and subsequently improve symptoms of SUI.